The invention is directed to a nozzle arrangement provided with means suitable to remove solids from its surface.
WO-A-2007125046 and WO-A-2007125047 describe a gasification reactor wherein a hot synthesis gas is produced by gasification of a coal feed. The hot synthesis gas is reduced in temperature by injecting a mist of water droplets into the stream of hot gas. A problem of having injection means for such a mist in the flow path for hot synthesis gas is that ash may accumulate on said means.
Means for removing ash in coal gasification processes are known. U.S. Pat. No. 5,765,510 describes a retractable soot blower for avoiding and dislodging accumulated soot and ash in the heat recovery devices as used in a coal gasification process.
A problem of using the soot blower of U.S. Pat. No. 5,765,510 in a process of either WO-A-2007125046 and WO-A-2007125047 is that the local gas flow direction will be disturbed. This local disturbance of the gas flow may result in that ash and not fully evaporated water comes into contact with the walls of the vessel. It is known that ash and liquid water can cause fouling that is not easy to remove.
GB-A-2061758 describes a radiant boiler wherein numerous nozzles are present to blow gas along the heat exchange surfaces to avoid solids accumulating on said surfaces. A problem with such an arrangement is that solids may still accumulate on the nozzles themselves.